Removable drop-in type back-pressure valve for drill strings



H. T. MILLER REMOVABLE DROP-IN TYPE BACKFPRESSURE Oct. 20, 1953 VALVE FOR DRILL STRINGS Filed Aug. l0, 1949 Fig 7 JNVENToR.

Herber 7.' Mil/er ATTORNEYS Patented Oct. 20, 1953 orf V'B EMQVA-BLSE DROP-IN TYPE BACK-PRES- TSURE 'FOR DRILL STRINGS Herbert fr. Miller, Houston, mex.

Application August 10, 1949, Serial'No. 109,514

` 2 claims. (ci. 25e-2s) This inventionrelates to '.a back rpressure valve vwhich is adapted `to'be droppedirito position `in a -drill string employed inthe rota-rymethod Aof drilling wells yand which lis adapted vto be removed yfrom the string =by1means Vof a wireline without requiring the removalof the string from the Well.

It is an object of this invention to :provide .a back pressure Vvalve-which Vmay be dropped linto position in a drill stringso as :to seat therein while the drill'string-is vin the well.

It is a further object of this invention `to Vprovideafback pressure valve whichmay be raised from its seated position in f a l drill string .without requiring therremoval-of the drill string from 'theWelL It is valso an object'ofthisinvention to provide a back pressure valve which is adapte'ddzo permit the passage of uidtherethrough as it descends into position in a drill'string.

It is `still fa further object of :this :invention to providea back pressurevalvezofthis(class which is` adapted Ito latch i,intoseated position in a drill fstringfand which isfadapteditoLbaunlatched when -it may be desired :to vremove the `valve from ythe drill string,

It is a further object of this ,invntiQn .to lprovide a back pressure ralvefof ithisiclass which is vadgalpted ,to permit fluid to QW .dovimwaldly therethrough A.when-it is ,seated n a tdrill string vwhich `,is rbeing removed from the well.

It .-is yet v.another zabject .of `,this invention to provide :a Iibaok pressure valve which is adapted :to remain seated while permitting iiuid to pass ltherethi'ougli during the drilling Operation, .and "which is adapted toclose upon Athe exertion of backpressurerfrom belowfthelseatfthereof, `ther@- by providing 1a blowout peventer zmans Within v"the vdrill :string .as it drills.

`Other and further Iobjects of :this invention will .be apparent `when the epeciication is Ycon- ,rsidered ,in connection with #the drawings, .in iwhch:

Figure 51;,is a sectional felevation yshowing the 'valve "with the mandrel 'thereof seated Atherein @and before :the :seating :member 'thereof has seatedptofclosetheimandrel;

Figs 2 is a sectional-elevation showing the valve when'the-seatingmember hasseated to .close the 4passage :through the fmandrel;

Fig. .f3 is 1a @fragmentary .sectional l*elevation 1 taken along linelIi--ily of `-1iig."2

Fig. is-/asectional plan viewitaken along line 4--4 of Fig. 2.

Fig .is anfenlarge'd@sectionalelevationfofithe mandrel valve latching and operating :mechanism,,asshownzin'Figk Fig. 6 isa sectional elevation, similar to 'Fig-f5, showing the mandrel valveunlatched;

Fig. "lis a sectional elevation taken along `:line `'I---l of Fig. k6;

Fig. 18 is .a `fragmentary sectional .elevation taken along line 8.-8 'ofFign ,12.

The valve 'l in :generalcomprses Ya body Ior sub `l and a mandrel or -mandrel vassembly :3. The sub or housing 2 is Aadapted for connection,

fas to a drilling bit, by :the .pinor threaded male end 4 :at the lower end,` fand at fthe upper `end thereof it `lhasa femaleor :threadedbox-.portion :5

-which adapts rit :for connection Ito: drill :string ele ments, asdrill collarsortoolijoints, above:the2bit.

:cates downwardly Withslottediports 4|25 'through the periphery of the'lower section It ofzthe body The uppersection lII yof 'thefbody lIsl "liasfe4 seal member -18 therearound which ts -ivithin the Isealing seat 7 of the .fsub 2; .and the :upper section I1 also provides .a .valve seat 'L9 :at @the lower end thereof.

As shown in' Fig. 5, .the flangefiof `thedilihlllai' flange member 22 frits Vwithin the lowerzmandrel body section Ii6. y'The latch i23.3iS-;Sh0wn'pvoted upon the pin v23 lwhich extends facross 'thefslot 156', vas shown `:in Fig. '7, to lbe supported-,inane mandrel end :2:4 on reither side rolf the vslot 15'.

When this latch `.23 lis engaged in 4the not-,eh

'33 Lin 'the valve stem 29, and when Aftheitension spring 28 is connected at its zunperiend vinto the'ring 21 yon the nut 26 on `gthe lower fend of the member'ZZ, and at `its lower Fend into :the rings! Aonthe spear Y3l;iitheiiangelibears upon the latch 23,'andthe mandrelbodyz iisfconneeted to the valve stem 2.9 jbyrthesenelements whereinabove described, includingffthe resllientmember or spring28. At the upper endnf the .valvecstem 29` "the .valve seating member `:Slltof fthe @valve Vmember |13 is :provided eto :seat AAWithin the :valve v'seat t9.

@a cage member u Le :innemen-assunte ene 3 mandrel body II, and this cage member has pivotally mounted therein the latching arms 38, which are adapted to swing inwardly and outwardly through the slots 39 in the upper portion of the cage member 34.

A spear 4| is provided which terminates downwardly in the ring member 42, which in assembly surrounds the lower portions 43 of the latching arms 38. The point 44, a central extension of the stem. 45 of the spear 4I, is of a configuration to spread the arms 38 outwardly to latch beneath the shoulder 6 of the sub 2, as shown in Fig. 2.

'Ihe cage 34 terminates upwardly in side guide plates 46 which are adapted to guide the mandrel assembly 3 through the opening 4l within the sub 2 above the shoulder 6. These side guide plates 46 have the spring housing 48 connected to the tops thereof, and this housing has the spring 49 therein to bear in the notches U and 5I of the spear stem 45, which passes through the top 52 of the spring housing. The stem 45 terminates lupwardly in the spear head 55, to which a wire line or similar lifting means may be attached.

'Ihe back pressure valve I may be utilized by installing the sub or housing 2 thereof in the bottom portion of a drill string, preferably just above the bit. Then when it is desired to bring the drill string out of the well, as when the bit is to be changed, the mandrel assembly 3 may be dropped into the drill string at the top of the well and it will descend thereinto, the latch 23 being in the notch 33, as shown in Fig. l. In its descent, iiuid within the drill stem may pass through the slotted ports I5, the annular passage I4, and out through the ports I2 .as the mandrel assembly 3 passes downwardly, thereby minimizing the resistance of fluid within the mandrel assembly to its downward passage. In cases, as when substantial uid resistance may be expected within the drill string, fluid may be pumped from the top of the well with sufficient force to overcome such resistance and force the mandrel .assembly 3 downwardly.

When the mandrel assembly 3 contacts the sealing seat 1, the seal I8 therearound seals within this seat and the mandrel is stopped by the tapered portion 8 of the sub 2. Then fluid is pumped with considerable force from the top of the well, and this fluid acts upon the seating .member at the top of the valve stern 29, and

also upon the upper surface of the spear point 32, to force the valve member I3 downwardly. When this occurs the latch 23 is freed from the notch 33, and the flange 25 oi the tubular flange member 22 bears on the top of the latch 23 as it seats on the shoulder 2| and thereby retains it in the position shown in Fig. 2. Then the pump at the top of the well is stopped, and this relief of pressure upon the valve member I3 permits the tension spring 28 to contract and move it upwardly to seat against the valve seat I9, the notch 33 passing upwardly past the latch 23 to the position -shown in Fig. 2.

passes into engagement therewith, thereby latchfing the spear 4I against undesired upward motion which might prematurely unlatch the manr-drel assembly 3 from its position Within the sub 2.

'145.v '52.A welltool as claimed in claim 1 in which With the mandrel assembly 3 thus in latched position within the sub 2, when the drill stem is raised, as in making trips out of the well, the weight of the fluid in the upper portion thereof will force the seating member 3D downwardly, but just suiciently so that iluid may flow downwardly through the seat I9. Then when the upward motion of the drill string is discontinued, the valve member 30 will seatv again; its functioning in this manner being determined by the preregulated reaction of the tension spring 28. Thus as the drill string is raised, stand by stand, from the well, the fluid therein is transferred step by step downwardly through the valve seat I9, and the pipe of the drill stern, which is removed at the top of the well, comes out in a substantially dry condition so that a minimum of the circulating fluid is wasted.

The provision of the back pressure valve of this invention serves an additional purpose in this manner. Should an excessive pressure be encountered n the vicinity of the bottom of the well, as the finding of gas or oil under excessive subterranean pressures, the seating element 3Q of the valve member I3 will be forced upwardly to seat against the seat I9, thereby providing against the gas or oil blowing upwardly and out at the top of the well.

It is also a feature of this invention to Vprovide a mandrel assembly 3 which may be easily withdrawn from a drill string when it may be no longer needed therein. This is simply accomplished by lowering a means, as a wire line, to attach to the spear head 55, and then the exertion of an upward pull on the wire line will move the spear 4I and the ring 42 thereof upwardly to bring the arms 38 in the position shown in Fig. l so that they may pass through the opening 4l and so that the elements of the mandrel assembly 3 therebelow may also be withdrawn upwardly therethrough.

Broadly this invention considers a back pressure valve having a mandrel, or a mandrel assembly, which may be dropped or pumped into position in the valve sub thereof and which may be withdrawn therefrom, leaving the valve sub as a part of the drill string assembly.

What is claimed is:

1. I n a well tool, the combination of, a tubular housing having a shoulder therein and being adapted for connection into the tubular pipe string employed in the rotary method of drilling wells, a valve seat in said housing, a tubular mandrel having an external seating means thereon and a valve seat therein and being adapted to descend said pipe string to position said seating means in seated position in said housing valve seat to'seal off said housing, a valve in said mandrel adapted to seat in said mandrel valve seat to seal off said mandrel, said mandrel comprising a latch means pivoted thereto and a latch setting means adapted to move axially with relationY to said latch means upon the impact of the seating of the mandrel to force said latch means outwardly to latch under said shoulder to anchor said mandrel in ysaid housing, said mandrel also including means to maintain said valve latched in open position and operable responsive to fluid pressure exerted from the top of the well to release said valve for closing, said tubular mandrel having communicating openings from the interior thereof above and below said mandrel valveA seat to permit fluid to pass through said mandrel with said mandrel valve latched in open position.

said latch setting means has means thereon adapted to be grasped by a wire line grapple means on a wire line lowered from the top of the well, said latch setting means also having means thereon adapted, upon the lifting upwardly on said wire line, to retract said latch means inwardly whereby said mandrel may be raised through said housing to pass by said shoulder.

HERBERT T. MILLER.

References Cited in the 111e of this patent UNITED STATES PATENTS Number Name Date Harrington July 25, 1933 Barrett et a1 Nov. l2, 1935 Newton Apr. 11, 1939 Baker et al Jan. 14, 1941 Muhlbach Nov. 25, 1941 Spencer Sept. 29, 1942 

